That said it's true that Apple does do some R&D that requires an in-person presence, but the number of people doing that stuff is tiny, and the vast majority of it is done entirely in software anyway.
Why is FANG trying to go back to the office? Because they all recently paid for multi-billion dollar headquarters. In the new remote economy these are useless plots of real estate, and they either haven't accepted this yet, or need to save face.